ADVANCED DEMOGRAPHIC SITUATIONS BASED ON LAG MODELS

Research and forecasting of time series based on models with lags is offered, as well as calculation of a reliable forecast based on data on birth rates in Ukraine. Economic modeling is one of the important modern tools for assessing the impact of technologies on the economic sector in order to obtain an optimal solution. Economic evaluations can be based on several different modeling approaches, each with its own strengths and weaknesses. The relevance of the use of economic and mathematical models for the purpose of studying demography is connected with the need to study population and migration processes, as well as for further planning and implementation of the country's economic and social development. In every sphere of the economy, there are phenomena that are interesting and important to study in their development, as they evolve over time. Prices, economic conditions, industrial processes, and demographic data tend to change over time. The set of measurements of this kind of indicators depending on time is a time series. The goals of studying time series can be different. It is possible, for example, to try to predict the future on the basis of knowledge of the past, to control the process that generates the series, to try to find out the mechanism underlying the process, to clear the series of components that obscure its dynamics, or simply to briefly describe the characteristic features of the series. When studying the relationships between indicators or when analyzing their development over time, not only the current value of the variables, but also some previous values in time, as well as time itself, are used as explanatory variables. Models of this type are called dynamic. In economic analysis, dynamic models are used quite widely. This is quite natural, because in many cases the influence of some economic factors on others is not carried out immediately, but with some delay − a lag. The object of research is the mathematical model of the interdependence of the vector time series "Births in Ukraine for January 2005 − July 2012." The data are chosen quite relevantly, because without a preliminary demographic forecast it is impossible to imagine the prospects of industry and consumption of goods and services, housing construction, development of social infrastructure, health care and education, pension system and solutions to geopolitical problems.